In order to promote safety, it is desirable to engage a sprinkler system as quickly as possible in the event of a fire. For example, minimizing the delay between when a fire is detected and when the sprinkler system is fully dispensing water may help to minimize or eliminate damage.
Dry pipe sprinkler systems are in frequent use today. Dry pipe sprinkler systems provide advantages relative to wet pipe sprinkler systems. For example, due to the presence of water in the piping of a wet pipe sprinkler system, the wet pipe sprinkler system could be rendered inoperable at low temperatures if the water freezes. Conversely, the fact that water is not present in the piping of a dry pipe system until the system is engaged (e.g., a fire is detected) allows dry pipe systems to be used in cold environments, such as unheated buildings, parking garages, etc.
The National Fire Protection Association (NFPA) 13 standard provides that every sprinkler system shall fulfill the requirement that the system is working in full operation pressure within sixty (60) seconds after the first sprinkler has been activated. Such a requirement typically does not present an issue in connection with a traditional sprinkler system (e.g., a wet pipe sprinkler system) because water starts to flow immediately through the nozzle after sprinkler activation and in traditional dry pipe sprinkler systems due to low air pressure (e.g., a low total mass of air) in the pipe and the use of relatively large nozzles. Also traditional dry pipe sprinkler systems may face challenges in trying to meet the (60) second target when the dry pipe section volume is relatively large, though. Conversely, in water mist dry pipe systems, the air pressure is initially relatively large (e.g., approximately 25 bar) and the air channels of the nozzles are relatively small (e.g., approximately 1 mm in diameter). This combination of high air pressure and small nozzles in a water mist dry pipe system presents challenges in terms of obtaining full water pressure in a timely fashion.